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    <script>
        function excel_time_to_timestamp (excelTime) {
            const second = 25569,
                day_timestamp = 24 * 60 * 60 * 1000;
            var dt = new Date((+excelTime - second) * day_timestamp)
            return dt.getFullYear() + '-' + (dt.getMonth() + 1) + '-' + (dt.getDate())
        }

        var time = excel_time_to_timestamp(43543)
        console.log(time);
    </script>
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